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authorStefan Klug <stefan.klug@ideasonboard.com>2024-08-20 16:51:43 +0200
committerStefan Klug <stefan.klug@ideasonboard.com>2024-09-23 16:42:45 +0200
commiteb6edfb69e8a778269371d15dd5ff5b2e5f94b96 (patch)
tree5e96d4f7cf3c5ab185d8ca983438ea3cf1750a09 /src/ipa/libipa/lsc_polynomial.h
parentb9d4fc82d9a40fefe914eef27b022e73dc0f8ec0 (diff)
ipa: libipa: Add lsc polynomial class
Add a basic class to represent polynomials as specified in the DNG spec for vignetting correction. Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Diffstat (limited to 'src/ipa/libipa/lsc_polynomial.h')
-rw-r--r--src/ipa/libipa/lsc_polynomial.h105
1 files changed, 105 insertions, 0 deletions
diff --git a/src/ipa/libipa/lsc_polynomial.h b/src/ipa/libipa/lsc_polynomial.h
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+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Ideas On Board
+ *
+ * Helper for radial polynomial used in lens shading correction.
+ */
+#pragma once
+
+#include <algorithm>
+#include <array>
+#include <assert.h>
+#include <cmath>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/span.h>
+
+#include "libcamera/internal/yaml_parser.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(LscPolynomial)
+
+namespace ipa {
+
+class LscPolynomial
+{
+public:
+ LscPolynomial(double cx = 0.0, double cy = 0.0, double k0 = 0.0,
+ double k1 = 0.0, double k2 = 0.0, double k3 = 0.0,
+ double k4 = 0.0)
+ : cx_(cx), cy_(cy), cnx_(0), cny_(0),
+ coefficients_({ k0, k1, k2, k3, k4 })
+ {
+ }
+
+ double sampleAtNormalizedPixelPos(double x, double y) const
+ {
+ double dx = x - cnx_;
+ double dy = y - cny_;
+ double r = sqrt(dx * dx + dy * dy);
+ double res = 1.0;
+ for (unsigned int i = 0; i < coefficients_.size(); i++) {
+ res += coefficients_[i] * std::pow(r, (i + 1) * 2);
+ }
+ return res;
+ }
+
+ double getM() const
+ {
+ double cpx = imageSize_.width * cx_;
+ double cpy = imageSize_.height * cy_;
+ double mx = std::max(cpx, std::fabs(imageSize_.width - cpx));
+ double my = std::max(cpy, std::fabs(imageSize_.height - cpy));
+
+ return sqrt(mx * mx + my * my);
+ }
+
+ void setReferenceImageSize(const Size &size)
+ {
+ assert(!size.isNull());
+ imageSize_ = size;
+
+ /* Calculate normalized centers */
+ double m = getM();
+ cnx_ = (size.width * cx_) / m;
+ cny_ = (size.height * cy_) / m;
+ }
+
+private:
+ double cx_;
+ double cy_;
+ double cnx_;
+ double cny_;
+ std::array<double, 5> coefficients_;
+
+ Size imageSize_;
+};
+
+} /* namespace ipa */
+
+#ifndef __DOXYGEN__
+
+template<>
+struct YamlObject::Getter<ipa::LscPolynomial> {
+ std::optional<ipa::LscPolynomial> get(const YamlObject &obj) const
+ {
+ std::optional<double> cx = obj["cx"].get<double>();
+ std::optional<double> cy = obj["cy"].get<double>();
+ std::optional<double> k0 = obj["k0"].get<double>();
+ std::optional<double> k1 = obj["k1"].get<double>();
+ std::optional<double> k2 = obj["k2"].get<double>();
+ std::optional<double> k3 = obj["k3"].get<double>();
+ std::optional<double> k4 = obj["k4"].get<double>();
+
+ if (!(cx && cy && k0 && k1 && k2 && k3 && k4))
+ LOG(LscPolynomial, Error)
+ << "Polynomial is missing a parameter";
+
+ return ipa::LscPolynomial(*cx, *cy, *k0, *k1, *k2, *k3, *k4);
+ }
+};
+
+#endif
+
+} /* namespace libcamera */